Paper feeding apparatus



April 3, 1962 R. E. BUSCH ET AL PAPER FEEDING APPARATUS 2 Sheets-Sheet 1 Filed -Jan. 26, 1959 PIE-5- 'l April 3, 1962 R. E. BUSCH ETAL 3,028,063

PAPER FEEDING APPARATUS Filed Jan. 26, 1959 2 Sheets-Sheet 2 FIEL 4c United States Patent Ofifice 3,028,053 Patented Apr. 3, 1962 3,028,063 PAPER FEEDING APPARATUS Richard E. Busch, La Puente, and Chris A. Christolf, San Gabriel, Qalifl, assignors to Clary Corporation, San Gabriel, Calif, a corporation of California Filed Jan. 26, 1959, Ser. No. 788,969 6 Claims. (Cl. 226-30) This invention relates to paper feed mechanisms for use in conjunction with data processing equipment or the like and has particular reference to positive feed mechanisms including feed sprockets for feeding paper strips.

As is well known, when an accurate feeding of a paper strip is required, the paper is preferably formed with sprocket pin perforations and i fed by a sprocket having sprocket pins thereon which engage such perforations to advance the paper.

Such sprocket mechanism is generally satisfactory, but difficulty is encountered when driving relatively thin paper and/ or when the paper is pulled by the sprocket means through guide devices or the like which create relatively heavy drag on the paper. In such cases, because of the small area of contact of the sprocket pins against the edges of the sprocket perforations in the paper, the pins tend to distort or even tear the paper surrounding such perforations. Also, when the drag or loading of the paper becomes excessive, difficulty is encountered in stripping the paper from the sprocket pins. These problems are aggravated when the sprocket drive is intermittently driven at relatively high acceleration and deceleration rates.

It therefore becomes a principal object of the present invention to overcome the above noted defects in present sprocket-type paper strip advancing mechanisms.

The present invention is based on applicants discovery that by utilizing a roller in frictional engagement with the paper and located ahead of the feed sprocket, with an absence of any drag applied to the paper intermediate the roller and the sprocket and, by driving the roller at a peripheral speed slightly in excess of the peripheral speed of the sprocket, a highly accurate drive can be obtained without any tendency for the sprocket pins to distort or tear the sprocket perforations, even though an excessive drag is applied to the paper.

The manner in which the above and other objects of the invention are accomplished will be readily understood on reference to the following specification when read in conjunction with the accompanying drawings, wherein:

FIG. 1 is a sectional view through a printing machine embodying a preferred form of the present invention.

FIG. 2 is a transverse sectional view taken substantially along the line 22 of FIG. 1, illustrating the paper feeding sprocket.

FIG. 3 is a transverse sectional view taken along the line 33 of FIG. 1, illustrating the friction drive roller.

FIG. 4 is a sectional plan view taken substantially along the line 4-4 of FIG. 1.

Referring to the drawings, the printer illustrated therein is basically of the type disclosed in detail in the co-pending patent applications of Witt et al., Serial No. 770,719, filed October 30, 1958, and since matured into Patent No. 2,915,968 issued on December 8, 1959, and Christoff et 211., Serial No. 787,543, filed January 19, 1959, and since matured into Patent No. 2,910,936 issued on November 3, 1959. Reference may be had to these applications for a complete understanding of the basic principle of operation of the printer. However, it is to be understood that the invention may be equally well applied to other forms of data processing equipment or the like embodying feeding mechanism for a paper strip.

The machine includes a printing drum 11 carrying drum is rotated While moving up and down a slight amount relative to printing platens (not shown) carried by a stationary guide block 12. The latter also guides a paper strip 13 between the printing drum and the platens.

The paper strip 13 is arranged in fan-folded form, having sprocket perforations 14 (FIG. 3) equally spaced along both edges thereof, and weakened fold or score lines 15 along which the strip is normally bent to assume its fan-folded formation.

The paper strip is stacked in a lower compartment 16 of a cabinet generally indicated at 17 and is drawn through a funnel-shaped guide chute 13 and thence around the guide block 12 as it passes a printing point or station P directly above the printing drum.

According to the present invention, the paper is drawn through the machine by a friction roller 19 and a sprocket roller 20 spaced apart and operating in unison, as will appear presently. The paper strip is then fed downward- 1y into an accumulating compartment 21 located directly above the compartment 16.

The sprocket 20 is carried by a shaft 22 which is rotatably mounted in bearings formed in side plates 23 and 24. Suitable means (not shown) is provided to incrementally advance the sprocket following the printing of each line of type at the printing station P.

The roller 19 and sprocket 20 have reduced diameter sprocket sections 25 and 26, respectively, over which is fitted an endless cog belt 27 which meshes with the teeth of the sections 25 and 26, and which forms the driving means for driving the roller 19 at the same angilar speed as the sprocket 20 is driven.

The roller 19 has two relatively soft sleeves 28 and 29 of rubber or the like attached thereon on opposite sides of the belt 27 to frictionally drive the paper strip thereover.

The sprocket 20 has two spaced enlarged diameter sections 3%) and 31, located on opposite sides of the belt 27 and over which the paper strip moves. The portion of the sprocket intermediate the sections 30 and 31 is reduced in diameter to receive a rearwardly extending tongue 32 of a guide plate 33, the latter being secured between the side plates 23 and 24. Forwardly extending tongues, i.e. 34 on the plates 33, extend partially around the roller 19 on opposite ends of the rubber sleeves 28 and 29. Other tongues, i.e. 34, on the plate extend on opposite sides of sprocket pins 35 on the sprocket.

A wall member 38 is spaced above the guide plate 33 to form a threading chute to facilitate initial threading of the strip 13 onto the sprocket 20. The latter is attached to the side plates 23 and 24 and its rearward portion extends partially around the sprocket, adjacent the tips of the sprocket pins 35, to prevent the strip from accidentally slipping off the pins.

A stripper plate 40 is attached between the side plates 23 and 24- below the sprocket 20 to prevent the paper ship from clinging to the sprocket pins as it enters the compartment 21. The stripper plate has upwardly extending fingers 41, 4 2 and 43 which extend into the reduced diameter sections of the sprocket.

According to the invention, the outer diameters of the roller sleeves 28 and 29 are slightly larger than the diameters of the sprocket sections 30 and 31 about which the strip 13 is wrapped. In practice, the optimum diameter difference has been found to be approximately .060 inch, but such diameter will vary with different conditions such as the frictional characteristics of the material of the sleeves, the stiffness and frictional charactenistics of the paper, etc.

In operation, a certain amount of drag is imparted to the paper strip as it is fed through the machine due to the frictional engagement of the paper with the surface of the guide block 12 and due to the relatively sharp radius around which the paper passes after leaving the printing station. Since the roller 1? is intermediate the drive sprocket 2t) and the source of frictional drag, the roller will tend to frictionally drive the paper ahead of the sprocket. Therefore, no load will be applied to the sprocket pins at this time. However, as a portion of the strip between the roller and the sprocket becomes slightly slack or limp, it tends to slip slightly on the roller, permitting the sprocket to take up a minute amount of slack. Thus, the paper will again frictionally grip the surface of the roller to be advanced ahead slightly until it again becomes somewhat slack. Accordingly, the sprocket pins never entirely drive the paper and therefore there is no tendency for the sprocket pins to tear the perforations regardless of the amount of drag applied to the strip. However, the sprocket pins become effective to accurately control the drive of the paper. Further, since no excessive forces are applied to the paper by the sprocket pins, the paper will easily strip off of the sprocket.

it will be noted that the guide member 33 is located slightly below the plane of the paper strip as it passes between the roller 19 and the sprocket. Thus, the paper does not normally touch the guide member, except during threading. However, in cases where the distance between the roller and sprocket is considerable, the paper upon becoming slack will tend to lay on the guide member.

Although we have described our invention in detail and have therefore used certain specific terms and language herein. it is to be understood that the present disclosure is illustrative rather than restrictive and that changes and modifications may be made without departing from the spirit or scope of the invention as set forth in the claims appended hereto.

Having thus described our invention, what we desire to secure by'United-States Letters Patent is:

l. A device for feeding a paper strip having sprocket perforations therein comprising means forming a source of drag for said strip, a sprocket wheel having sprocket pins engageable in said perforations, a roller frictionally engageable with said strip intermediate said source of drag and said sprocket, said roller having frictional characteristics capable of driving said strip without slippage when said strip is tensioned over said roller, means for driving said sprocket, and means for driving said friction roller at a peripheral speed slightly in excess of the peripherai speed of said sprocket, the frictional engagement between said roller and said strip being such that said roller drives a portion of said strip in engagement therewith intermittently at a higher rate of speed than said sprocket drives a portion of said strip which is in engagement with said sprocket pins.

2. A device for feeding a paper strip having sprocket perforations therein comprising a roller, a paper strip wrapped partially around said roller, said roller having frictional characteristics capable of driving said paper without slippage when said strip is tensioned over said roller, means forming a source of drag for said strip, said means being located on one side of said roller, a feed sprocket on the opposite side of said roller, said sprocket having sprocket pins engageable in said perforations, means for rotating said sprocket, and means for rotating said roller at a peripheral speed slightly in excess of the peripheral speed of said sprocket, the frictional engagement between said roller and said strip being such that said roller drives a portion of said strip in. engagement therewith in increments at a higher rate of speed than said sprocket drives a portion of said strip which is in engagement with said sprocket pins.

3. A device for feeding a paper strip having sprocket perforations therein comprising means forming a source of drag for said strip, a sprocket wheel having sprocket pins engageable in said perforations, a roller engageable with said strip intermediate said source of drag and said sprocket, said roller being arranged to cause said strip to wrap partially itherearound whereby to effect a frictional engagement between said roller and said strip, said roller having frictional characteristics capable of driving said strip without slippage when said strip is tensioned over said roller, means for rotating said sprocket, and means for rotating said roller at a peripheral velocity slightly in excess of the peripheral velocityof said sprocket, the frictional engagement between said roller and said strip being such that said roller intermittently and alternately drives a portion of said strip in engagement therewith at a higher rate of speed than said sprocket drives a portion of said strip which is in engagement with said sprocket pins and then slips relative to said strip.

4. A device for feeding a paper strip having sprocket perforations therein comprising means forming a source of drag for said strip, a sprocket wheel having sprocket pins engageable in said perforations, a roller engageable with said strip intermediate said source of drag and said sprocket, said roller being arranged to cause said strip to wrap partially therearound, the surface of said roller having such frictional characteristics as to be capable of driving said strip independently of said sprocket and without slippage when said strip is tensioned over said roller, means for rotating said sprocket, and means for rotating said roller at a peripheral velocity slightly in excess of the peripheral velocity of said sprocket, the frictional engagement between said roller and said strip being such that said roller drives a portion of said strip in engagement therewith until a second portion of said strip intermediate said roller and said sprocket becomes slack whereupon said roller rotates relative to said strip until said second portion becomes taut.

5. A device for feeding a paper strip having sprocket perforations therein comprising means forming a source of drag for said strip, a sprocket wheel having sprocket pins engageable in said perforations for pulling said strip past said source of drag, a roller engageable with said strip intermediate said source of drag and said sprocket, said roller being arranged to cause said strip to Wrap partially therearound, said roller having a relatively soft peripheral surface of such frictional characteristics as to be capable of driving said strip independently of said sprocket and without slippage when said strip is tensioned over said roller, the path of said strip intermediate said roller and said sprocket being free from any retarding influence, means for rotating said sprocket, and means for rotating said roller at a peripheral velocity slightly in excess of the peripheral velocity of said sprocket, the frictional engagement between said roller and said strip being such that said roller drives a portion of said strip in engagement therewith until a second portion of said strip intermediate said roller and said sprocket becomes slack whereupon said roller rotates relative to said strip until said second portion becomes taut.

6. A device for feeding a paper strip having sprocket perforations therein comprising means forming a source of drag for said strip, a sprocket wheel having sprocket ins engageable in said perforations for pulling said strip past said source of drag, a roller engageable with said strip intermediate said source of drag and said sprocket, said roller being arranged to cause said strip to wrap partially therearound at an angle less than said roller having a relatively soft peripheral surface of such frictional characteristics as to be capable of driving said strip independently of said sprocket and without slippage when said strip is tensioned over said roller, the path of said strip intermediate said roller and said sprocket being free from any retarding influence, means for rotating sm'd sprocket, means for rotating said rolier at a peripheral velocity slightly in excess of the peripheral velocity of said sprocket, and means forming a guide-way between said roller and said sprocket, said guide-way being arranged to guide said strip in a plane extending substanti-ally tangentially of said roller and said sprocket, the frictional engagement between said roller and said strip being such that said roller alternately drives a portion of said strip in engagement therewith until a second portion of said strip intermediate said roller and said sprocket becomes slack and thereafter said roller rotates relative to said strip until said second portion becomes taut.

References Cited in the file of this patent UNITED STATES PATENTS Smith Aug. 18, Jackson Aug. 13, Heisler June 24, Allen May 18, Mabon Aug. 29, Gopperton Aug. 17, 

